Relay tube



May 4, 1937.' H. c. REN-rscHLER 2,079,362

RELAY TUBE Filed May l, 1934 lNvl-:NToR H c'. /Pf/vrsos/H? BY ATroRNEY' jatenteol May 45, 1.937

TENT OFFICE RELAY TUBE Harvey C. Rentsehler, East Orange, N. J., as'- signor, by mesne assignments, to Westinghouse Electric and Manufacturing Company, East'A Pittsburgh, Pa., a corporation of Pennsylvania Application May 1, 1934*', Serial N0. 723,311-

Yis concerned. The tube described in said patent comprises an envelope containingv a cathode, a starting anode and a main or service anode. A small projection or starting tip extends from the cathode and terminates adjacent the starting anode. The cathode is of cylindricai form and surrounds both the main and starting anodes. The envelope also contains a rare gas such as argon at a pressure of about 5 to 8 millimeters.

In the course of my experimentations with tubes of this character and especially when employing the same in the circuit set forth in my patent application Serial No. 328,243 liled on December 24, 1928, now Patent No. 2,037,924, dated April 21, 1936, and assigned to the same assignee as the present invention, I have found that improved and more constant results may be obtained with tubes containing the improvements of the present invention.

Briefly my invention contemplates the employment of relatively small electrodes, a relatively high gas pressure and one or more electrodes surfaced with a substance such as thorium having a low voltage drop at the surface thereof. The envelope of the tube should be composed of ya dielectric as for example Pyrex or other glass having a low surface leakage characteristic when in an atmosphere of high humidity.

An object of my invention is to provide a relay tube having improved and constant electrical characteristics.

Another object of my invention is to provide a simple glow relay tube of the three electrode and gaseous conduction type in which a predetermined discharge initiated between two oi said electrodes is always sulicient to cause initiation between two main electrodes when a predetermined potential is applied between the two main electrodes.

These and other objects of my invention will be readily apparent from the following description and drawing wherein,

Figure 1 represents a view in elevation, with part of the envelope broken away, of a tube embodying my invention;

Figure 2 represents a View similar to Figure 1 (Ci. Z50-275)' and taken at ninety degrees to View' illustrated in' Figure 1; and

Figure 3 .represents a cross sectional view, online III-III of Figure 1, in the direction of the arrows. y 5

As shown in the drawing, my improved tube comprises an envelope IE! havinga press II in. which are sealed lead-in conductors I2 and I3 extending interiorly and exteriorly' off said envelope and connected to suitable contact pins 10 I5 carried by a base IG.v Although but'two contact pins I 5 are indispensable, I Vprefer to employ four contact pins with two of `them being dummles.

The upper portions II and I 9 of the lead-in l5 conductors I2 and I3 and the lower portion of the support I8 are embedded in the press II and supported thereby. The conductors II and I8 are located at the ends of the press and the conductor I9 is between conductors I1 and I8. The conductor I9 extends slightly upwardly, then outwardly and then upwardly and substantially parallel to the conductors I'I and I 8. The conductor I8 is a dummy support wire terminating in the press. All of the conductors have the major portion thereof composed of nickel.

Respectively carried by supports I'l, I8 and I9 are cylindrical rods 20, 2I and 22, with rod 2| being the starting anode, rod 22 the cathode, and rod 2U, the main anode. These rods 20, 2I and 22 are about 150 mils in diameter and about of an inch in length and are clamped, or by other appropriate means, secured to short nickel rods welded to the supports I'I, I8 and I9. 'I'he thorium electrodes 20, 2| and 22 are so arranged 35 that they are parallel and adjacent to each other, with the rods 2l and 22 spaced about one millimeter apart and the rods 20 and 22 spaced about three millimeters apart.

The cathode is located off the line of the press 40 and between the anodes 20 and 2I so that when ionization occurs between the starting anode 2I and the cathode 22, ionized gas is directly in the vicinity of the space between the cathode 22 and anode 28 so that a discharge may readily occur 4- therebetween. Glass rods 23 surround the supports Il and I8 along the major portion of the lengths thereof. These rods 23 are sealed to the press II and serve to prevent discharge and electrical leakage between the supporting posts for 5 the electrodes. A lead-in conductor 24, electrically connected to a contact cap 25, is electrically connected to the starting anode 2l.

The contact cap 25 is located at the uppermost part of the envelope and thus is remotely dis- 55 posed from the contact pins I5, so that leakage along the envelope shall be inappreciable. In order to further enhance the usefulness of this tube as a relay device in my circuit hereinbeiore referred to, the envelope is composed of a glass having a low electrical leakage characteristic, especially when in an atmosphere of high humidity. For thispurpose Iprefr to employ A'Pyrex or othertype' of gl'ass'having said property.

One other improvement that I have made in the present invention is to employ a rare gas such as argon Within the envelope at a pressureof about 20 to 50 millimeters of mercury, and preferably between 30 and 35 millimeters f mercury. With a tube of the characterabove described, it is possible to apply a p'otentialfbetween"the main anode 20 and the cathodel 22, insufficient to normally cause breakdown-r-aiischarge'therebetween. Upon ya predetermined potential being applied between said cathode 22 and starting `afn'ode'121-I, '-.afdi'scharge ioccurs :therebetween to ionize the gas within the envelopefand in the "vicinity of 'theespace betweenthe main Aanode 2llV arid 'cathode 22. lue" toitlris'y ibniation of Ithe gas, the resistance of the path is reduced'be- *tweentheimainfanode "and the cathode 22, so that thelpotentialappliedthereacross is nnow suf- `iicier'it to causefbreakdown therebetween. The improved 'tuberwhich f1 have ld'esr'zribed isfcon'stant in voperation. Although 'have'idescribed the invention -with some fparticularity, lit 'is not "to be 'limited therelbyfbuton'lyby thefprior art.

starting anode and cathode being spaced a distance of about one millimeter and said main anode and cathode being spaced a distance approximately three times the distance between said starting anode and cathode, the gas in said envelope'being at a .pressure between twenty and fty millimeters of mercury.

2. A relay tube comprising an envelope enclosing a press, a plurality of supports extending from said press, a plurality of electrodes secured to said supports, said electrodes including a vmain anode, astarting anode,and `a cathode, all of said electrodes being formed of thorium, cylindrical in form, having their longitudinalaxes substantially parallel, and spaced apart bodily, and argonat a pressure of fromfabout 30-to 35 m. 1m. -oflmercury enclosed in lsaid envelope, said vstarting anode and cathode being spaced yapart al distance-,,o;f about 1 In. m., and said main anode `:and cathode being spaced apart a distance of about 3 m. m.

HARVEY C. RENTSCIV-ILER. 

